1. Field of the Invention
The present invention is an electronic ballast and lamp system for controlling the power to one or more gas discharge lamps. It is directed to the problems of present ballasts and gas discharge lamps which waste energy through excess heat generation, and which lack control options and which have inherent problems associated with the filaments in standard fluorescent lamps.
The present invention is able to power one or more gas discharge lamps, such as fluorescent lamps, without standard filaments. The filaments are replaced with unconnected single electrodes.
2. Prior Art Statement
Fluorescent lamps are used extensively throughout office buildings, schools, hospitals, industrial plants for lighting, as plant grow lights for outdoor lighting, and for many other uses. The power to these lamps are controlled by ballasts which have inherent problems. While standard fluorescent lamps with standard ballasts and less sophisticated electronic ballasts offer some benefits over other lighting techniques, such as lower energy use for comparable light output, these ballasts still waste energy through excessive heat generation, they lack the features available with the present invention and the life of the lamp is limited because of failure of the filaments. Standard ballasts use bulky energy wasting transformers to create a high voltage, low frequency signal to excite the lamp filaments creating thermionic emissions. The present invention uses a low voltage, high frequency signal to cause the electrodes to radiate energy. Existing ballasts require specific impedance matching to a specific lamp design. The present invention can power a wide range of lamp sizes without modification.
Using the present invention, lamps will burn cooler, last longer and produce a brighter light while using less electricity. The present invention also has a more sophisticated level of control then is available from the present state of the art. It can dim the lamps, delay power-up to improve lamp life, sense when a lamp is missing and respond accordingly by reducing power or shutting down completely, and it can be controlled remotely or by a programmable unit. The present system is also able to light its lamps in extremely low temperature because there is no need to heat the filaments.
U.S. Pat. No. 5,105,127 discloses a ballast for control of a two-pin fluorescent lamp. However, this device utilizes a complex system of supplying square pulses comprised of a high frequency signal. These "pulses" are then modulated to achieve dimming.
U.S. Pat. No. 5,039,920 also discloses a ballast for control of a two-pin fluorescent lamp. This device utilizes an even more complex system to supply a wave with a "noncontinuous sinusoidal shape" to the lamps. Effectively these lamps see a single cycle of a sine wave followed by a "notch" or dead zone and then another single cycle.
U.S. Pat. No. 4,392,087 discloses a device to power two-pin fluorescent tubes but requires a tuning capacitor and hence can not accept different lamps loads without modification. Further, dimming is accomplished by decreasing voltage.
U.S. Pat. No. 4,876,485 discloses a device which, while used to power standard fluorescent lamps, teaches the ability to power such lamps with an open filament. However, the frequency is fixed and thus cannot be changed to dim the lamps and cannot automatically be adjusted to match the lamp load.
Thus while there is extensive prior out in the ballast and gas discharge lamp area, none teaches an electronic ballast to power and control gas discharge lamps, e.g. two-pin fluorescent lamps, by the simple regulation of frequency of the power signal to the lamps such that the load can be matched, and the lamps can be dimmed.